The invention relates to an assembly comprising an integrated mass air flow sensor and a broadband silencer that is adapted for use in the air induction system of an internal combustion engine.
In many internal combustion engines, a mass air flow sensor (MAFS) is used to measure the air flow rate entering the engine and, in turn, provide an output signal that is used to maintain a desired air-fuel ratio. Maintaining a desired air-fuel ratio is important to achieve optimal engine performance, fuel economy, and engine emissions.
Because the output signal, and in particular the signal-to-noise ratio of a typical mass air flow sensor can be adversely affected by air turbulence, mass air flow sensors preferably measure air flow having uniform velocity and minimal turbulence over the complete range of engine operating conditions.
The effect of air turbulence on a mass air flow sensor can be particularly problematic under conditions of low flow rate such as during engine idling. Moreover, low flow rate turbulence and its attendant adverse impact on MAFS output can be exacerbated if the MAFS is located in a relatively large diameter flow path.
Many high performance internal combustion engines such as those having turbochargers or superchargers require high intake air flow rates. These high flow rates are usually achieved by providing relatively large diameter flow paths in the air induction system. In addition to requiring high intake air flow rates, such high performance engines preferably project a particular acoustic signature, which can be obtained by incorporating into the air induction system an acoustic device such as a tunable (e.g., broadband) silencer.
The space available for components such as mass air flow sensors and broadband silencers is typically limited due to design and esthetic considerations. Furthermore, the high flow rates required by many high performance engines are at odds with the low turbulence requirements of mass air flow sensors that are included in these engines.
Accordingly, it would be advantageous to provide a broadband silencer and a mass air flow sensor that are compatible with both the flow rate and the space requirements of many high performance engines.